1. Field of the Invention
The present invention relates to an apparatus for controlling a rotary shaft in a machine tool or the like.
2. Description of the Related Art
When controlling a rotary shaft in a machine tool, it is general practice to perform feedback control by detecting the rotational angle/rotational speed of a rotating body and by computing the amount of control of a servo motor from the difference between the detected angle/speed and its command value.
However, in the control of an indexing table in a machine tool, for example, the rotating body may vibrate due to the presence of a low-rigidity part such as a joint connecting between the rotating body and the detector.